Unveiling the nature and fate of the almost-dark cloud AGC 226178 through Hi mapping
文献类型：期刊论文
| 作者 | Sun, Yu-Zhu2,7,8; Zhang, Hong-Xin2,7; Brinks, Elias5; Smith, Rory4,6; Li, Fujia2,7; Kim, Minsu3,18; Oh, Se-Heon3,18; Lin, Zesen17; Kim, Jaebeom3,18; Sun, Weibin2,7 |
| 刊名 | Astronomy and Astrophysics
 |
| 出版日期 | 2025-09-01 |
| 卷号 | 701 |
| 关键词 | galaxies: clusters: intracluster medium galaxies: dwarf galaxies: evolution radio lines: galaxies |
| ISSN号 | 0004-6361 |
| DOI | 10.1051/0004-6361/202555150 |
| 产权排序 | 第17完成单位 |
| 文献子类 | Journal article (JA) - |
| 英文摘要 | Context. The origin of extragalactic, almost dark Hi clouds with extreme gas-to-stellar mass ratios remains poorly understood. Aims. We investigated the nature and fate of the almost dark cloud AGC 226178, projected within the Virgo cluster, which exhibits an Hi-to-stellar mass ratio of approximately 1000. Methods. We present deep single-dish Hi mapping from the Five-hundred-meter Aperture Spherical Telescope (FAST), complemented by high-resolution interferometric data from the Very Large Array (VLA), as part of the Atomic gas in Virgo Interacting Dwarf galaxies (AVID) project. Together, these observations provide the highest-quality Hi analysis to date of an almost dark cloud, in terms of the combination of spatial resolution and sensitivity. Results. The FAST data reveal a short low-velocity tail extending towards the dwarf galaxy VCC 2034, which was previously proposed as a possible origin for AGC 226178. However, VCC 2034 itself exhibits a line-of-sight asymmetric Hi feature and a cometary morphology that indicates a stripping event unrelated to AGC 226178. VLA observations reveal a velocity gradient across AGC 226178, along with a clumpy internal structure. The velocity dispersion within the cloud exceeds the thermal line width, indicating the presence of turbulence and/or unresolved random motions. The whole cloud cannot be gravitationally bound by the observed atomic gas alone. The resolved Hi clumps follow the standard Hi mass-star formation rate relation and a tight mass-size relation: those associated with star formation reach surface densities above the theoretical threshold for self-shielding. Conclusions. We conclude that AGC 226178 is a free-floating Hi cloud of unknown origin. The system appears to be in the process of disintegration. It is likely located well outside the Virgo cluster, as the preservation of its extended Hi morphology within the cluster environment would otherwise require a substantial reservoir of unseen molecular gas with a mass exceeding that of the observed Hi content. While confinement pressure from the hot intracluster medium may contribute to its stability, it is unlikely to be the dominant factor preventing its disruption. © The Authors 2025. |
| 学科主题 | 天文学 ; 天体物理学 ; 高能天体物理学 ; 星系与宇宙学 |
| URL标识 | 查看原文 |
| 资助项目 | N/A |
| 语种 | 英语 |
| WOS记录号 | WOS:001562399900003 |
| 资助机构 | N/A |
| 源URL | [http://ir.ynao.ac.cn/handle/114a53/28571]  |
| 专题 | 星系类星体研究组 |
| 作者单位 | 1.Department of Astronomy, Center for Galaxy Evolution Research, Yonsei University, Seoul, 03722, Korea, Republic of; 2.Department of Astronomy, University of Science and Technology of China, Hefei, 230026, China; 3.Department of Astronomy and Space Science, Graduate School, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul, Korea, Republic of; 4.Millenium Nucleus for Galaxies (MINGAL), Valparaíso, Chile; 5.Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB, United Kingdom; 6.Departamento de Fisica, Universidad Tecnica Federico Santa Maria, Avenida España, Valparaíso, 1680, Chile; 7.School of Astronomy and Space Science, University of Science and Technology of China, Hefei, 230026, China; 8.School of Physics and Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom; 9.State Key Laboratory of Radio Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100101, China 10.Yunnan Observatories, Chinese Academy of Sciences, Kunming, 652016, China; |
| 推荐引用方式 GB/T 7714 | Sun, Yu-Zhu,Zhang, Hong-Xin,Brinks, Elias,et al. Unveiling the nature and fate of the almost-dark cloud AGC 226178 through Hi mapping[J]. Astronomy and Astrophysics,2025,701. |
| APA | Sun, Yu-Zhu.,Zhang, Hong-Xin.,Brinks, Elias.,Smith, Rory.,Li, Fujia.,...&赵应和.(2025).Unveiling the nature and fate of the almost-dark cloud AGC 226178 through Hi mapping.Astronomy and Astrophysics,701. |
| MLA | Sun, Yu-Zhu,et al."Unveiling the nature and fate of the almost-dark cloud AGC 226178 through Hi mapping".Astronomy and Astrophysics 701(2025). |
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